May Help Alleviate Blood Shortage
Blood donors with hemochromatosis, a disorder in which iron accumulates in organs and body tissues, do not pose a greater risk to blood safety than other donors, according to the results of a study funded by the National Heart, Lung, and Blood Institute (NHLBI) and published in the September 26 issue of the Journal of the American Medical Association.
Hemochromatosis patients are treated with periodic phlebotomies or "blood letting" to remove excess iron from their body. Because these patients benefit medically and financially by giving blood (they don't have to pay for phlebotomy), there has been concern that they might donate despite having infectious disease risk factors and that their blood might be less safe. As a result, FDA regulations have not promoted blood donation from hemochromatosis patients.
"Hemochromatosis patients in this study had no more risk of transmitting viral infections than did other donors. This finding should help guide future decisions on blood donations by these patients. If people with hemochromatosis qualify as donors then that could potentially have a significant impact on the national blood supply," said NHLBI Director Dr. Claude Lenfant.
The study authors report that the issue of the acceptability of blood donations from patients with hemochromatosis becomes more relevant as concerns about eating contaminated beef lead to the implementation of new donor deferral policies based on a history of living or traveling in Europe or the United Kingdom.
Hemochromatosis affects 0.5 percent of white people living in the United States. Once considered rare, the disease is now believed by many to be the most common genetic disease of white Americans. There are few published data on the prevalence of the disease in minority populations.
While it seems like a relatively small pool of potential donors, people with hemochromatosis would give regularly since periodic donation is required to control their condition.
There have been varying estimates of the number of potential donations from hemochromatosis patients - some as high as 3 million units per year. Overall U.S. blood donations total about 13.9 million units per year, according to the American Association of Blood Banks.
The study involved an anonymous mail survey conducted in 1998 as part of The Retrovirus Epidemiology Donor Study (REDS). Survey respondents were from eight large U.S. blood centers. Of the 52, 650 blood donors who returned questionnaires, scientists identified 197 who reported a diagnosis of hemochromatosis. Analyses were restricted to donors who reported hemochromatosis and did not indicate some other health-related reason motivating them to donate blood.
Although nearly 46 percent of hemochromatosis donors reported that their primary motivation for donating was to treat their illness, the prevalence of unreported risk factors for transfusion-transmissible viral infections (TTVIs) was similar for patients with hemochromatosis (2 percent) and for donors who did not donate for a health reason (3.1 percent). The overall prevalence of positive screening tests for TTVI, a measure of possible viral infection, was also similar in both groups - 1.3 percent of hemochromatosis patients versus 1.6 percent of donors who did not have a health reason to donate.
"The importance of blood donations from hemochromatosis patients may increase even further. Recent improvements in diagnosis may lead to even larger estimates of hemochromatosis prevalence," said Dr. George Schreiber, principal investigator of the REDS coordinating center at Westat.
Prevalence estimates may also change as a result of an ongoing study funded by NHLBI that is screening large populations in an effort to find genetic markers for hemochromatosis.
Almost 90 percent of hemochromatosis donors in the survey gave blood at centers whose policy was to defer all hemochromatosis patients, thus restricting them from donating. The study authors propose several explanations for this, including the possibility that current risk factor screening at blood collection centers may not detect all cases of hemochromatosis. Alternatively, donors may either intentionally not report their condition so they can donate or they may fail to report their condition because of miscommunications with blood bank staff. They are not asked directly whether they have hemochromatosis but whether they have "a blood disease."
Current FDA regulations for blood donation do not prohibit blood from hemochromatosis patients. However, unless the blood center has an FDA variance, all blood that is drawn during therapeutic phlebotomies must be labeled and the source indicated. It is then up to physicians and their patients to decide whether they want to use the blood. Schreiber and REDS study co-authors note that labeled blood is usually not well accepted and is often discarded. In 1999, the FDA began granting variances to blood collection organizations that offer free phlebotomies to all patients with hemochromatosis. The variances allow blood to be collected from these patients without special labeling. However, to qualify for a variance, the blood collection organization must bear the cost of the free phlebotomies. Only a small percentage of licensed and registered blood collection facilities have requested and received variances.
To arrange an interview with an NHLBI scientist, contact the NHLBI Communications Office at (301) 496 - 4236. To interview Dr. Schreiber, call (301) 251-8203; to interview Ana Sanchez, MHS, of Westat, the lead author of the study, call (301) 251-2268.